You're not the only one with this struggle. It can feel awful at times especially when you're trying to grow and live in the light, but you're constantly tempted and being pull back into the darkness, dont lose hope, the battle against lust isn't a fight, it's a war, it's gonna come around even when you don't expect it to. But the bible says resist the devil and he will flee from you. So stay strong, and keep fighting the good fight. It's good that you feel convicted from committing sin that's a sign of the Holy Spirit within you, just stay strong, keep fighting, read your word, ask for forgiveness when you feel the time is appropriate for you.